20 CROCODILES. 



as the water recedes in the lake, they are here confined. The alligators thrash 

 them, and devour them whenever they feel hungry, while the ibis destroys all that 

 make towards the shore. By looking attentively on this spot, you plainly see the 

 tails of the alligators moving to and fro, splashing, and now and then, when missing 

 a fish, throwing it up in the air. The hunter marks one of the eyes of the largest 

 alligators, and as the hair-trigger is touched the alligator dies. Should the ball 

 strike one inch astray from the eye, the animal flounces, rolls over and over, 

 beating furiously about him with his tail, frightening all his companions, who sink 

 immediately ; whilst the fishes, like blades of burnished metal, leap in all directions 

 out of the water, so terrified are they at this uproar." 



During the pairing-season, which takes place in the spring, the males resort 

 to the land, and are but seldom seen ; while soon after the female deposits her 

 hard white eggs, which are said at times to be upwards of one hundred in number. 

 The nest in which the eggs are laid is generally placed among bushes or reeds, at 

 a distance of fifty or sixty yards from the water's edge ; the eggs themselves being 

 carefully covered with leaves and other vegetable matter. The heat engendered 

 by the decomposition of the latter, aids in the hatching of the eggs ; and when the 

 young appear, they are conducted to the water by the mother, who has all the 

 time remained on guard near the nest. 



Double-Tusked In the middle and lower Tertiary deposits' of both Europe and 



Alligators, the United States, the present group was represented by certain 

 extinct alligators (Diplocynodori) characterised by the presence of a bony armour 

 on the lower surface of the body, coupled with the circumstance that the fourth 

 tooth of the lower jaw was generally received into a notch in the side of the skull, 

 while the third lower tooth was as much enlarged as the fourth. Some of these 

 double-tusked alligators had short snouts, like their existing allies; but in one 

 from the London Clay this part of the skull was much produced, as in many 

 crocodiles. 



stumpy A small and short-nosed crocodile (Osteolcemus tetraspis) from 



Crocodile. West Africa, in the neighbourhood of Sierra Leone, where it was 

 discovered by Du Chaillu, presents much the same relationship to the true 

 crocodiles as is held by the alligators to the caimans. Thus, while the arrange- 

 ment of the teeth is similar to that obtaining in the true crocodiles, the nasal 

 bones extend forwards to divide the cavity of the nostrils into two halves. 

 Moreover, the upper eyelid is largely bony, while there are detached bony 

 plates on the lower surface of the body, as well as on the throat. The shield of 

 the neck is distinct from that of the back, and is composed of two or three pairs 

 of plates, of which the anterior ones are very large; while that of the back 

 comprises seventeen transverse rows of plates, the broadest row including six of 

 such plates. The ridges on the plates of the neck are strongly marked, but they 

 become very obscure in the two middle rows of the back. The fore-toes have 

 only rudimentary webs, although those of the hind-limbs are webbed for about 

 half their length. With the exception of parts of the head, tail, and back, which 

 are light brown with black markings, the coloration of the adult is uniform blackish 

 brown. Young specimens are, however, yellowish brown, spotted with black above, 

 and with bars of the same on the body and tail ; while the lower armour is black 



